The present invention concerns a device comprising:
at least one high-voltage circuit, and
a casing containing the circuit and having at least one opening which provides communication between the inside and the outside of the casing, electrical charges of opposite sign to that of the high voltage being likely to be present outside the casing and to enter the casing.
The invention applies in particular to a telecommunications satellite equipped with a device of the above kind.
Traveling wave tube amplifiers (TWTA) included in satellite telecommunications payloads have recently suffered malfunctions, and even complete failure, following the operation of ion thrusters used to control the position of the satellite.
The present invention addresses the above problem by opposing ingress of plasma generated by ion thrusters into the casings containing the power supply circuits of the TWTA and any leakage of electrical potential to the outside of the casings, such leakage encouraging the ingress of plasma by attracting a portion thereof to the vicinity of the high voltages present in the TWTA.
More generally, the invention aims to protect a device of the above type from electrical charges that can be present in the vicinity of its casing.
To be more precise, the present invention consists in a device of the above type which further includes:
protection means which do not block the opening and are adapted to oppose:
the ingress of said charges into the casing, and
the existence outside the casing of high potentials due to the high voltage of the circuit.
The protection means eliminate overloads and even short circuits that the plasma can generate in TWTA of a telecommunications satellite.
In a preferred embodiment of the device in accordance with the invention, the protection means comprise an electrically conductive plate outside or inside the casing, fixed and electrically connected to the casing, facing the opening and projecting over the periphery of the opening.
In one embodiment the protection means comprise two electrically conductive plates, respectively inside and outside the casing, fixed and electrically connected to the casing, facing the opening and projecting over the periphery of the opening.
The plate which is inside the casing is preferably covered with an electrically insulative material on the same side as the circuit.
In a preferred embodiment of the invention each conductive plate is a thin foil.
Instead of one or two plates, the protection means can comprise an electrically conductive grid which is fixed and electrically connected to the casing and which closes the opening.
The electrical charges of opposite sign to the high voltage come from a plasma, for example.
Each circuit can comprise a traveling wave tube amplifier or a power supply circuit of onboard equipment which uses voltages such that operation of the circuit can be interfered with by the presence of a plasma.
The invention also concerns a satellite comprising at least one ion thruster or operating in the presence of a natural plasma,
the satellite further comprising at least one device according to the invention, the electrical charges:
coming from the plasma generated by the ion thruster or from the natural plasma, or
being created artificially by a generator.